This is a difficult review because we have used C & J Air Conditioning and Heating Co. on two occasions. The first occasion, they saved us a lot of money after the manufacturer said that we had a very expensive problem. C & J charged us $200, and fixed the problem. The last time, it all reversed. C & J told us we needed to call the manufacturer, because after running diagnostics, they could not fix the problem. One of our zones was out, and come to find out, one of the 20 thermostats at the facility had a switch that had simply been turned to "Off", instead of being left on "Auto." These kinds of things happen, and we would probably use C & J Air Conditioning and Heating Co. if we had a mechanical problem, but would be less inclined if it presented as an electrical problem. But that is the reason why we lowered the service rating to Three Stars. I think C & J is a fine company, but the review needs to be based on what happened this last time.